Fluid cooled furnace structure



March 28, 1961 H. E. voGELl FLUID cooLED FURNACE STRUCTURE 2 Sheets-Sheet 1 Filed OGb. 9, 1957 March 28, 1961 H. E. VOGEL! 2,976,854

FLUID COOLED FURNACE STRUCTURE Filed OOb. 9, 1957 2 Sheets-Sheet 2 mvENToR L-T Harry E.Vogel W jm/,MI

FLUID cooLED FURNACE STRUCTURE Harry E. Vogeli, Alliance, Ohio, assignor to Salem- Broslus, Inc., Carnegie, Pa., a corporation of Penn- Sylvania Filed Oct. 9, 1957, Ser. No. 689,118

Claims. (Cl. 122-6) This invention relates to fluid cooled furnace structure and particularly to a furnace structure comprising uid cooled means for supporting refractory material within the furnace.

It is necessary in furnaces, particularly in elongated furnaces through which work passes while being heated or heat treated, to provide within the furnace bafe or other walls which are subjected to very high temperatures and which therefore require substantial maintenance. A customary way of building such a wall is to apply special shaped refractory brick to a lintel which may, for example, be an I-beam or a composite built up of structural shapes welded together. The joints between the bricks are cemented. The joints open up and the cement spalls out due to the temperature and the heat may then impinge directly against the lintel with consequent damage to the lintel itself as well as to the furnace brickwork. To repair the lintel and/or brickwork it is necessary to at least cool off the furnace and replace the brickwork, cementing in the new bricks. If the lintel has become damaged it at least has to be repaired and it may have to be replaced. Altogether the Vmaintenance problem has been a vexing one and maintenance expense has been high.

I have devised a uid cooled furnace structure obviating the disadvantages of the structures heretofore conventionally employed as above described. I utilize a hollow structural member for supporting refractory material within the furnace chamber and I provide for passing a huid coolant through the hollow structural member. The duid coolant may be gaseous or liquid. In some installations I prefer to employ air as a coolant while in other installations I prefer to employ water.

The hollow fluid cooled structural member which I employ may assume various shapes. I find that it is ldesirable that such structural member be of generally circular cross section, and I prefer to employ seamless pipe or tubing to most effectively guard against possible leakage. The structural member is preferably at least partially supported outside the furnace chamber. When possible I prefer to support the structural member entirely outside the furnace chamber so that the supporting means for the structural member is not subjected to the heat within the furnace chamber. When, for example, the structural member is a straight pipe extending through the furnace walls with its ends outside the furnace chamber and its central portion inside the furnace chamber I normally support the structural member entirely outside the furnace chamber, sealing the structural member to the furnace walls to inhibit leakage of hot gases through the walls about the structural member while at the same time permitting some relative expansion and contraction between the furnace walls and the structural member.

In certain instances the structural member may have a shape other than straight. For example, it may be of substantially U shape when it is designed to surround a ue and partially or entirely support brickwork or refrac Ytory of the flue. Normally lwhen a structural memberof generally U shape is employed its ends Will project out through the furnace Wall and its intermediate portion supports the iiue. In such case I provide means outside the furnace chamber supporting the ends of the hollow structural member and additional means intermediate the ends of the hollow structural member for assisting in supporting it, the additional means being preferably atleast primarily outside the flue.

The supporting of the hollow structural member at least to a considerable extent outside the furnace chamber and the provision for passing coolant therethrough substantially contribute to increased life of the furnace structure. The cooling effect of the coolant passing through the hollow structural member is felt not only by the structural member itself but also by the brickwork or refractory carried by it. Heat passes through the brick- Work or refractory and through the wall of the hollow structural member and is conducted away by the coolant. As a result the mean temperature of the brickwork or refractory is materially lowered, resulting in minimizing spalling out of the cement and hence substantially reducing maintenance.

I obtain a further `advantage by applying monolithic refractory material to the hollow structural member. Such refractory material has no openings such as occur between bricks and better withstands the heat of the furnace than does brickwork. At the same time it is much less expensive than special shaped refractory bricks. Still further, it may be much more easily and readily applied, and the labor cost incident to application of the mono* lithc refractory material is very much less than lthe labor cost incident to rebuilding of a brick Wall. Still further, and of utmost importance, repairs may be made without cooling the furnace. The monolithic refractory material may be gunned vonto the hollow fluid cooled structural member within the furnace by introducing an applicator or gun through a door or other opening in the furnace Wall `and thus applying the monolithic refractory material. Indeed this may even be done without interrupting the operation of the furnace in the heating or heat treating of material.

To aid in maintaining monolithic refractory material ,in place on the hollow fluid cooled `structural member I apply retaining means to the hollow structural member, the retaining means being outwardly projecting plates or shapes known in the art as gaggersf They are strategically located and preferably welded to the outside of the structural member so as to effectively maintain the mono lithic refractory material in place when it is gunned on as above explained.

In some cases my hollow fluid cooled structuralv member may be used for supporting brickwork and in vother cases monolithic refractory material may be applied to it,

and if the occasion requires both monolithic refractory material and brickworlt may be applied to and supported by the same hollow fluid cooled structural member.

When water is used as the coolant the water may contain sediment; water taken from streams normally contains sediment. To obviate settling or depositing of sediment within the hollow iluid cooled structural member I may provide means maintaining the sediment or solids in the cooling Water in suspension so that the solids will pass through with the circulating cooling water. To maintain the -solids in suspension in the ceiling water I preferably blow air through the cooling water. I desirably provide a conduit having spaced apart air outlet means having a portion disposed in the lower part of the hollow structural member and means for delivering compressed air to the conduit so that the air will pass through the spaced apart air outlet means and agitate the cooling water so as to maintain solids therein in suspension.

In certain cases, especially where long spans are involved, seamless tubing or pipe alone may not have the Patented Mar. 2S, 1961,

requisite structural strength to support the refractory material in'thefurnace. In such cases I provide strengthening means inside the pipe which in most cases I arrange generally vertically bridging the pipe from top to bottom. For example, I may introduce into the pipe an I-beam whose height is such that it is more or less snugly received within the pipe so as to extend in a generally Vertical plane diametrically of the pipe, and I may weld the I-beam in place within the pipe, although generally I prefer to maintain the I-beam in place without welding. The I-beam greatly strengthens the pipe and assists in carrying the load. When such a strengthening member is employed it may substantially divide the pipe internally into two or more less segregated conduits, one on each side of the strengthening member. When cooling water containing sediment or solids is employed as the coolant in such a situation I iind it desirable to provide at each side of the strengthening member means such as referred to above for maintaining the solids in suspension.

Other details, objects and advantages of the invention will become apparent as the following description of certain present preferred embodiments thereof proceeds.

In the accompanying drawings I have shown present preferred embodiments of the invention in which Figure l is a vertical longitudinal cross sectional view through a furnace having my invention applied thereto;

Figure 2 is a vertical cross sectional view to enlarged scale taken on the line lI-II of Figure l;

Figure 3 is a fragmentary elevational view of a portion of a furnace showing a straight hollow fluid cooled structural member;

Figure 4 is a vertical transverse cross-sectional View taken on the line IVIV of Figure 3, but with a portion cut away;

Figure 5 is fa View to enlarged scale partly in plan and partly in horizontal cross section and with a portion cut away showing a straight hollow uid cooled structural member;

Figure 6 is a view partly in elevation and partly in Vertical cross section and with a portion cut away of the structure shown in Figure 5;

Figure 7 is an enlarged vertical cross-sectional.viewY taken on the line VII-VII of Figure 6;

Figure 8 is an enlarged vertical cross-sectional view taken on the line VIII-VIII of Figure 6; and

Figure 9 is an enlarged Vertical cross-sectional view t-aken on the line IX-IX of Figure 6l.

Referring first to Figures l and 2, there is shown a billet heating furnace of the type through which billets pass more or less continuously to be heated. The billets may pass through the furnace by being pushed one against the other in well known manner, moving from right to left viewing Figure l and being supported upon a hearth 2. The entrance opening is normally closed by a door 3 and the discharge opening is normally closed by a door 4. The furnace has a roof 5, a floor 6, end walls 7 and side walls ES dening the furnace chamber. Burners 9 are provided for introducing into the furnace chamber hot products of combustion to apply heat to the billets passing therethrough. In general, except for the hollow fluid cooled structural members and related parts, the furnace may be more or less conventional and since such furnaces and their operation are well known to those skilled in the art I shall not describe in detail any portions of the furnace other than those to which my invention is applied.

In Figure l two applications of my invention are shown, one at the nose 10 and the other at the flue 11. I shall describe first the application of my invention at the nose 10 of the furnace. Outside of each of the side Walls 8 of the furnace is a supporting saddle 12 which may be made up o-f structural shapes welded together and which maybe supported upon an I-beam 13 forming a portion of the supporting structure for the furnace. Extending through the furnace side walls 3 and through the furnace chamber is a. hollow seamless steel pipe 14 of circular cross section. The pipe 14 constitutes a hollow fluid cooled structural member for supporting refractory material within the furnace chamber. Its ends are disposed outside the furnace chamber as shown in Figure 9 where they rest upon the supporting saddles 12, straps 15 securing the ends of the pipe 14 to the saddles 12. To structurally strengthen the pipe 14 I dispose in vertical position therewithin an I-beam 16. The I-beam cooperates with the pipe to provide a hollow iiuid cooled structural member of requisite strength to support'the refractory material required to be supported by the structural member. The l-beam 16 is shown as being maintained in position and in desired orientation by lugs or ears 16a welded to the inner faces of the end closure members 1Gb for the pipe 14 which are sealed to the pipe 14 and maintained in place by any suitable means such as bolts, not shown.y The ears 16a engage the opposite faces of the web of the I-beam at the ends thereof toV position the l-beam relative to the closure members 1615. Small rounded caps 16o of weld or other metal may be applied to the outer faces of the flanges of the I- beam to relieve the ends of the flanges of some of the load by engaging the inner surface of the pipe cooperatively with the ends of the flanges.

I provide for passing fluid coolant through the pipe 14. VThe coolant may be gaseous or liquid. In this partticular illustration the coolant is river water containing sediment or solids. It may be circulated through the pipe 14 in any appropriate path, as, for example, by being introduced at 17 and withdrawn at 1S. the I-beam 16 is cut away at 16d immediately inside the inlet 17 and outlet 18. Additional opening into the pipe are shown at 19 which may be used as desired in'connection with the circulation of the coolant, or they may be normally plugged and used for cleaning out the pipe if it should become clogged.

However, I guard against the pipe 14 becoming clogged by providing therein at each side of the I-bcam 16 a conduit 2t) having spaced apart air outlet means or holes through which compressed air delivered thereinto through a pipe 21 may be discharged. Each conduit `2t) passes through and is sealed to the closure memmebrs 16b and has its end remote from its connection with the pipe 21 closed by a plug 21a. The holes for emitting the compressed air are designated 22 in Figures 10 and l1. No attempt has been made to show them in Figures 8 and 12-14 although it is to be understood that they are present. The compressed air emltted through the holes 22 agitates the cooling liquid so as to maintain solids therein in suspension whereby the solids pass through with the cooling liquid and do not remain behind to clog the pipe 14.

Suitably applied to the outside of the pipe 14 are gaggers 23 whose function is to act as retaining means to hold in place monolithic refractory material to be applied to the pipe. The gaggers may be of any desired shape and may be applied where they will most electively perform their function. They are shown as being of generally l. shape and welded to the pipe at an end of one of the legs. However the particular `shape or shapes of the gaggers and the manner and place of application thereof on the pipe 14 do not Vconstitute limitations upon my invention.

Monolithic refractory material 24 is applied to the exterior of the pipe 14 bybeing gunned onto the pipe ina manner well known to those skilled in the art of thus applying monolithic refractory material. Access may be had to the pipe through a door or other opening in the furnace wall and the applicator or gun for applying the monolithic refractory material may be introduced'therethrough to apply the material. The gaggers assist 4in maintaining the monolithic refractory material in place and whensuch materialhas been applied the gaggers may be substantially or entirely embedded therein. The refractory material completely covers the metal pipe and protects it against the heat within the furnace chamber. The refractory material may be applied without cooling the furnace and indeed without interrupting its use. Since there are no joints such as occur between the bricks of brickwork there is much less likelihood of spelling of the refractory material than in the case of brickwork. The coolant within the pipe 14 conducts away heat and thus maintains the structure consisting of the pipe and refractory material at a reduced temperature, further assisting in prolonging its life.

'I'he furnace has flues 11 at opposite sides which are identical and each of which is partially mounted upon a hollow fluid cooled structural member 25 of generally U shape..

Thus, Whether the hollow fluid cooled structural member is straight or U-shaped, or perhaps L-shaped or otherwise shaped, it is at least partially, preferably, when possible, entirely, supported outside the furnace chamber and cooled by any appropriate coolant which reduces the temperature of the structure, whether monolithic refractory material or built-up brickwork or both are -applied thereto and carried thereby. The structure is economical to erect and requires less maintenance than conventional structures, and the labor cost incident to maintenance is greatly reduced. Thus I provide a furnace structure having many advantages but which may be provided and maintained at reduced cost.

While -I have shown and described certain present preferred embodiments of the invention it is to be distinctly understood that the invention is not limited thereto but may be otherwise variously embodied within the scope of the following claims.

I claim:

1. Furnace structure comprising walls, including generally upright walls, defining a furnace chamber, a pipe extending through at least one of the generally upright walls so as to be partly within and partly outside the space between opposed generally upright walls, means outside said space supporting the pipe, strengthening means disposed entirely within the wall of the pipe bridging the pipe, means for passing a coolant through the pipe and refractory material supported by the pipe inside said space for protection against heat therein.

2. Furnace structure comprising walls, including generally upright walls, defining a furnace chamber, a hollow structural member extending through at least one of the generally upright walls so as to be partly within and partly outside the space between opposed generally upright walls, defining a furnace chamber, means outside said space supporting the hollow structural member, means for passing cooling liquid which may contain solids through the hollow structural member, refractory material supported by the hollow structural member inside said space for protection against heat therein and pneumatic means maintaining solids in the cooling liquid in suspension to obviate undesirable deposition of solids in the hollow structural member.

3. Furnace structure comprising walls, including generally upright walls, defining a furnace chamber, a hollow structural member extending through at least one of the generally upright walls so as to be partly within and partly outside the space between opposed generally upright walls, means outside said space supporting the hollow structural member, means for passing cooling liquid which may contain solids through the hollow structural member, refractory material supported by the hollow structural member inside said space for protection against heat therein and means blowing air through the cooling liquid maintaining solids in the cooling liquid in suspension to obviate undesirable deposition of Solids in the hollow structural member.

4. Furnace structure comprising walls, including generally upright walls, dening a furnace chamber, a hollow structural member extending through at least one of the generally upright walls so as to be partly Within and partly outside the space between opposed generally upright walls, means outside supporting the hollow structural member, means for passing cooling liquid which may contain solids through the hollow structural member, refractory material supported by the hollow structural member inside said space for protection against heat therein, a conduit having spaced apart air outlet means having a portion disposed in the lower part of the hollow structural member and means for delivering compressed air to the condiut so that the air will pass out through the space apart air outlet means and agitate the cooling liquid so as to maintain solids therein in suspension.

5. Furnace structure comprising walls, including generally upright walls, defining a furnace chamber, a pipe extending through at least one of the generally upright walls so as to be partly within and partly outside the space between opposed generally upright Walls, means outside said space supporting the pipe, means for passing cooling liquid which may contain solids through the pipe, refractory material supported by the pipe inside said space for protection against heat therein, strengthening means disposed entirely within the wall of the pipe and arranged generally vertically bridging the pipe from top to bottom and 'at least to some extent dividing the space within the pipe, a conduit having spaced apart air outlet means having a portion disposed lin the lower part of the pipe at each side of the strengthening means and means for delivering compressed air to the conduits so that theair will pass out through the spaced apart air outlet means and agitate the cooling liquid so as to maintain solids therein in suspension.

References Cited in the file of this patent UNITED STATES PATENTS 1,085,138 Knox Jan. 27, 1914 1,220,444 Naismith Mar. 27, 1917 1,581,545 Pracke Apr. 20, 1926 1,656,782 Efstathiou Jan. 17, 1928 2,268,558 Bailey i Ian. 6, 1942 2,420,715 Millward May 20, 1947 2,511,676 Morton June 13, 1950 2,550,725 Schultz May l, 1951 2,705,476 Hardgrove Apr. 5, 1955 FOREIGN PATENTS 878,143 Germany June l, 1953 

